Inter-cell interference coordination (ICIC) is a scheduling strategy for obtaining a high data rate in a cell edge region in consideration of inter-cell interference. Basically, ICIC involves setting specific constraints in an uplink and downlink scheduler in order to coordinate interference due to transmission in adjacent cells. If transmit power of some frequencies is suppressed in a specific cell, interference sensed at the frequencies in adjacent cells will be lowered, and such spectra may be used to provide a higher data rate to users in the adjacent cells.
A 3GPP LTE system supports a function of exchanging interference indicators, such as Relative Narrowband Tx Power (RNTP), RNTP threshold, UpLink High Interference Indicator (UL HII), and UL Interference Overload Indicator (UL IOI), between base stations in order to implement a variety of ICIC schemes. The interference indicators are defined in a frequency domain and used to manage interference between adjacent cells by limiting transmission in the frequency domain.
Meanwhile, a technique for performing ICIC in a time domain (time-domain ICIC), as well as in the frequency domain, for ICIC in a heterogeneous network environment has been proposed.
However, in the time-domain ICIC, a size of an interference signal between adjacent cells greatly differs according to whether or not a subframe is used. Accordingly, interference must be coordinated for each subframe through a transmit power control (TPC) command, causing frequent generation of TPC signaling.
Further, it is difficult for accurate transmit power control in a time-domain ICIC method to be performed when the size of the interference signal exceeds a previously set power control range.